Known conveyor belt lubricants are employed in applications in which good gliding contact between solid surfaces, for instance glass and metal, or plastic and metal must be ensured.
These applications include bottle filling and conveying plants, where the lubricants are applied to the conveyor belts to ensure the trouble-free conveyance of bottles on the belt. In many known systems, a soap such as potash-based soft soap is used as the lubricant.
As a substitute for the soap-based lubricants, a variety of synthetic conveyor belt lubricants including certain amine compounds are being used. These synthetic lubricants have been described in, for example, EP-A-372,628, U.S. Pat. No. 5,073,280 and EP-A-767,825.
These conveyor belt lubricants are generally supplied as concentrates and use concentrations of such concentrates are usually prepared by applying typical dilution rates of 0.2-1.0% by weight concentrate in water depending on the friction requirement and the water type.
Such aqueous belt lubricants having a use concentration of the active lubricating ingredients of significantly less than 1% by weight have been satisfactorily applied for many years.
On the other hand, the application of these aqueous lubricants has also resulted in high water usage rates and relatively high effluent costs for the user.
Furthermore, when used as conventionally intended these aqueous lubricants flow off the conveyor track surface treated therewith, resulting in a waste of chemical and water, and causing a slippery floor surface which may constitute a hazard to operators working in the immediate environment.
Lubrication in a wide range of lubricating applications involving moving metal parts including metal shaping operations, such as drilling, cutting and drawing, by means of the deposition of a lubricant film has been known for many years. For instance, U.S. Pat. No. 5,549,836 discloses a mineral oil-free aqueous lubricant composition useful for producing a lubricant film and suitable for use in the above-mentioned types of lubricating applications involving moving metal parts.
We have now surprisingly found that certain specific liquid formulations suitable for producing a “dry” lubricant film, can be advantageously used as a conveyor belt lubricant, whereby the above-described problems observed when using the aqueous conveyor belt lubricants of the prior art are effectively overcome.
In particular, we have found that such liquid formulations have both good lubricating properties and adequate cleaning characteristics.
In this connection, a “dry” lubricant film is defined as a lubricant film which remains on the surface onto which it is applied as a liquid, and which, consequently does not flow off, or is easily removable from, said surface.